Method of connecting floor joist to bearer in floor frame

ABSTRACT

A floor frame comprised of floor joists and bearers formed from rolled strip steel, the floor joist including an end portion, said end portion being substantially orthogonal to a longitudinal axis of the floor joist and butting a bearer which lies substantially orthogonally to the floor joist, the floor joist and bearer being fixed together with fixing elements which pass through the end portion and bearer.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims the benefit of Australian Provisional Patent Application No. 2005 900839 filed Feb. 23, 2005, the teachings and disclosure of which are hereby incorporated in their entireties by reference thereto.

FIELD OF THE INVENTION

The present invention relates to steel floor frames.

SUMMARY OF INVENTION

The present invention provides a method of connecting a floor joist to a bearer in a steel floor frame, and to a steel floor frame incorporating said connection methodology, according to the following claims. Preferred features of the invention will be apparent from the dependant claims and from the following description of the preferred embodiment.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in a non-limiting manner with respect to a preferred embodiment in which:

FIG. 1 is an exploded perspective view of a 2-storey structure, with the wall frames omitted for clarity;

FIG. 2 is a partially-exploded, perspective view of a floor frame;

FIG. 3A is an end view of a floor joist;

FIG. 3B is a side view of the floor joist of FIG. 3A;

FIG. 3C is a top view of the floor joist of FIG. 3A;

FIG. 4 is an external side view of a bearer;

FIG. 5 is a perspective view of a floor frame attached to upper and lower wall

frames;

FIG. 6 is an exploded view of FIG. 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

With reference to FIG. 1, there is illustrated a 2-storey structure comprised of roof trusses 12 and floor frames 10. The upper and lower wall frames have been omitted for clarity.

Referring now to FIG. 2, there is illustrated a portion of a floor frame 10. Floor frame 10 is comprised of floor joists 14 and bearers 16, each of which is formed from C-section structural members rolled from light-gauge strip steel. The floor frame is covered by floor sheeting 18 which is shown in cutaway view in FIG. 2.

As can be seen, the C-section floor joist 14 is formed from a pair of flanges 20, each extending from a central web 22. Each flange 20 terminates with a flange return 24.

With reference now to FIGS. 3A to 3B, it will be noted that the end of the floor joist 14 (i.e. web 22, flanges 20 and returns 24) is crimped or compressed such that the end of the floor joist can be inserted into the bearer 16 as shown in FIG. 2. Note also that the flange returns of the C-section bearer 16 are removed in order to enable the C-section floor joist 14 to be received within the C-section bearer 16.

The end of web 22 is folded over at 90 degrees in order to form an end portion or bracket 26, such that the end of the floor joist 14 is box-like in shape. The end portion 26 includes a number of dimples 28, each of which is centrally punched to receive a fixing member such as a rivet or screw.

With reference to FIG. 4, it will be noted that the web 30 of the C-section bearer 16 is likewise dimpled and punched at 32. The dimples assist in aligning the floor joist 14 relative to the bearer 16 during assembly, and additionally provide resistance against shearing when secured together via a rivet or the like.

Referring now to FIGS. 5 and 6, there is illustrated the floor frame in combination with upper and lower wall frames 34 which were omitted from FIG. 1. Each wall frame is comprised of a bottom plate 36, top plate 37, and studs 38. As illustrated, both plates and studs are also formed from C-section steel members, which are again rolled from light-gauge strip steel.

As can be seen, the flanges 42 of the bearer 16 each include slots 44 for receiving a connection tab 40. Floor sheeting 18 likewise includes an aligned slot such that the connection tab 40 can extend downwardly through the floor sheeting 18 and flange 42 for connection with the web 22 of the floor joist 14 via screws, rivets or the like. It will be observed that the upper end of the connection tab 40 extends upwardly through a slot formed in the bottom plate 36 of the wall frame 34 for connection (again via rivets or screws) with the stud 38 of the wall frame. By this mechanism, the connection tab 40 connects the stud 38 of the wall frame 34 directly to the web 22 of the floor joist 14.

With reference to FIG. 1, it will be noted that each of the roof trusses 12 similarly includes a downwardly depending tab which extends downwardly through a slot formed in the web of the top plate of the upper wall frame for connection with the web of the stud of the upper wall frame. It will be recalled that the wall frames are omitted from FIG. 1.

Whilst in the preferred embodiment it is an extension of the web of the floor joist which is folded over to form the end portion which butts the bearer, a person of skill in the art will appreciate that one or both of the flanges, or even one or both of the flange returns, could be used to form the folded end portion or bracket which butts against the web of the bearer.

The provision of an end portion or bracket which can be butted with the bearer allows fixing of the floor joist to the bearer to occur from the exterior perimeter of the floor frame, rather than from above and below the floor frame as would occur in the absence of the end portion. Additionally, a joint made according to the present invention provides the floor frame with superior stiffness. The presence of the end portion or bracket acts to stiffen the joist, bearer and the connection. The end portion or bracket is formed during the rolling process which means that assembly of the floor frame simply involves applying the rivets to the joists and bearers.

Whilst the invention has been described with reference to a particular preferred embodiment, it will be understood that the following claims are not limited to the preferred embodiment. 

1. A method of connecting a floor joist to a bearer in a floor frame, where each of the floor joist and bearer is formed from rolled strip steel, the method comprising: forming an end portion on the floor joist, said end portion being substantially orthogonal to a longitudinal axis of the floor joist; butting the end portion of the floor joist with the bearer which lies substantially orthogonally to the floor joist; fixing the floor joist and bearer together with fixing elements which pass through the end portion and bearer.
 2. A method as claimed in claim 1, wherein each of the floor joist and bearer is substantially C-shaped in cross-section, and wherein the end of the floor joist is crimped in order to facilitate reception of the end of the floor joist within the bearer.
 3. A method as claimed in claim 2, wherein the bearer includes a web, flanges and flange returns, and wherein the flange returns are removed in order to receive the end of the floor joist.
 4. A method as claimed in claim 2, wherein the end portion is formed from a folded over section of the web of the floor joist.
 5. A floor frame comprised of floor joists and bearers formed from rolled strip steel, the floor joist including an end portion, said end portion being substantially orthogonal to a longitudinal axis of the floor joist and butting a bearer which lies substantially orthogonally to the floor joist, the floor joist and bearer being fixed together with fixing elements which pass through the end portion and bearer.
 6. A floor frame as claimed in claim 5, wherein each of the floor joist and bearer is substantially C-shaped in cross-section, and wherein the end of the floor joist is crimped in order to facilitate reception of the end of the floor joist within the bearer.
 7. A floor frame as claimed in claim 6, wherein the bearer includes a web, flanges and flange returns, and wherein the flange returns are removed in order to receive the end of the floor joist.
 8. A floor frame as claimed in claim 6, wherein the end portion is formed from a folded over section of the web of the floor joist. 